Configure a self-managed Oracle database for CDC

This page describes how to configure change data capture (CDC) to stream data from a self-managed Oracle database to a supported destination , such as BigQuery or Cloud Storage.

You can configure your self-managed Oracle database to work with the following CDC methods:

Binary log reader ( Preview )
LogMiner API

These methods specify how Datastream accesses your log files. For more information about the binary log reader and the LogMiner API, see Work with Oracle database redo log files .

For detailed instructions about how to configure your source Oracle database for each of these methods, see the sections that follow.

Configure your self managed Oracle database for binary log reader

To configure your self-managed Oracle database for use with the binary log reader CDC method, perform the following steps:

Select one of the following methods to access your log files:
- Automatic Storage Management (ASM): if you select this option, you need to create a dedicated ASM connection, and provide its details when you create your connection profile.
- Database directories: if you select this option, you need to create database directory objects that point to the redo log files and the archived log files, and grant READ access to the directories to your database user:
```
 CREATE 
  
 DIRECTORY 
  
  DIRECTORY_NAME_1 
 
  
 as 
  
 ' ONLINE_REDO_LOGS_PATH 
' 
 ; 
 CREATE 
  
 DIRECTORY 
  
  DIRECTORY_NAME_2 
 
  
 as 
  
 ' ARCHIVED_REDO_LOGS_PATH 
' 
 ; 
 GRANT 
  
 READ 
  
 ON 
  
 DIRECTORY 
  
  DIRECTORY_NAME_1 
 
  
 to 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 READ 
  
 ON 
  
 DIRECTORY 
  
  DIRECTORY_NAME_2 
 
  
 to 
  
  USER_NAME 
 
 ; 
```
Replace the following:
- DIRECTORY_NAME_1 : the name of the directory for the online redo log files.
- DIRECTORY_NAME_2 : the name of the directory for the archived redo log files.
- ONLINE_REDO_LOGS_PATH : the path to the directory where online redo log files are to be stored.
- ARCHIVED_REDO_LOGS_PATH : the path to the directory where archived log files are to be stored.
- USER_NAME : the name of the database user to whom you want to grant READ access.
If you select the binary log reader method and use database directories, you need to provide the redo log and archived log directory names when you create your stream.
Verify that your database is running in ARCHIVELOG mode.

To do so, sign in to your Oracle database and run the following command at the SQL prompt:

SELECT LOG_MODE FROM V$DATABASE;
1. If the result is ARCHIVELOG , then move on to the next step.
2. If the result is NOARCHIVELOG , then you'll need to enable ARCHIVELOG mode for your database.
3. Run the following commands when logged in as SYSDBA :
```
 SHUTDOWN 
  
 IMMEDIATE 
 ; 
 STARTUP 
  
 MOUNT 
 ; 
 ALTER 
  
 DATABASE 
  
 ARCHIVELOG 
 ; 
 ALTER 
  
 DATABASE 
  
 OPEN 
 ; 
```
4. Archived log files consume disk space, so you'll want to configure the DB_RECOVERY_FILE_DEST_SIZE parameter for your database. Use this parameter to specify (in bytes) the hard limit on the total space to be used by target database recovery files. By setting this parameter, you can manage the tradeoff between protecting the database from running out of disk space and the stream failing because of log position loss.
Define a data retention policy for your database by running these Oracle Recovery Manager (RMAN) commands:
```
 TARGET 
  
 / 
 CONFIGURE 
  
 RETENTION 
  
 POLICY 
  
 TO 
  
 RECOVERY 
  
 WINDOW 
  
 OF 
  
 4 
  
 DAYS 
 ; 
```
You use the TARGET / command to start an RMAN client and connect to the source database. See Making Database Connections with RMAN .

We recommend that you retain backups and archive logs for a minimum of 4 days, and 7 days is recommended.

Running this command will restart your database instance so that the changes you made to the database can take effect.
Return to the SQL prompt of the database tool that you're using to configure the Oracle log file rotation policy. We recommend setting a maximum log file size of no more than 512MB.
Enable supplemental log data . To do so, first enable minimal database-level supplemental logging by running the following command:
```
 ALTER 
  
 DATABASE 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
 ; 
```
Next, choose whether to turn on logging for specific tables or the entire database.

To log changes only for specific tables, run the following command for each table that you want to replicate:
```
 ALTER 
  
 TABLE 
  
  SCHEMA 
 
 . 
  TABLE 
 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
  
 ( 
 ALL 
 ) 
  
 COLUMNS 
 ; 
```
Replace the following:
- SCHEMA : the name of the schema that contains the table.
- TABLE : the name of the table for which you want to log changes.
To replicate most or all tables in your database, consider turning logging on for the entire database. Run the following command to enable supplemental log data for the entire database:
```
 ALTER 
  
 DATABASE 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
  
 ( 
 ALL 
 ) 
  
 COLUMNS 
 ; 
```
The supplemental logging mode must be set to ALL . You can't set this mode to PK_ONLY .

Grant the appropriate privileges directly to the user account that's used to connect to your database. Note that these grants don't work when assigned to a role, for example. To do so, run the following commands:

 GRANT 
  
 SELECT 
  
 ON 
  
 GV_$LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 GV_$LOGFILE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 GV_$ARCHIVED_LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 GV_$INSTANCE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 GV_$STANDBY_LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 V_$INSTANCE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 V_$PDBS 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 V_$TRANSPORTABLE_PLATFORM 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 V_$DATABASE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 V_$PARAMETER 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 COL$ 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_OBJECTS 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_TABLESPACES 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_ENCRYPTED_COLUMNS 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_EXTENTS 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 CONNECT 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 CREATE 
  
 SESSION 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ANY 
  
 TABLE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 READ 
  
 ON 
  
 DIRECTORY 
  
 ONLINELOG_DIR 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 READ 
  
 ON 
  
 DIRECTORY 
  
 ARCHIVELOG_DIR 
  
 TO 
  
  USER_NAME 
 
 ;

Replace USER_NAME with the name of the user account that you intend to use to connect to your database.

Configure your self managed Oracle database for LogMiner

Verify that your database is running in ARCHIVELOG mode.

To do so, sign in to your Oracle database and run the following command at the SQL prompt:

SELECT LOG_MODE FROM V$DATABASE;
1. If the result is ARCHIVELOG , then move on to step 2.
2. If the result is NOARCHIVELOG , then you'll need to enable ARCHIVELOG mode for your database.
3. Run the following commands when logged in as SYSDBA :
```
 SHUTDOWN 
  
 IMMEDIATE 
 ; 
 STARTUP 
  
 MOUNT 
 ; 
 ALTER 
  
 DATABASE 
  
 ARCHIVELOG 
 ; 
 ALTER 
  
 DATABASE 
  
 OPEN 
 ; 
```
4. Archived log files consume disk space, so you'll want to configure the DB_RECOVERY_FILE_DEST_SIZE parameter for your database. Use this parameter to specify (in bytes) the hard limit on the total space to be used by target database recovery files. By setting this parameter, you can manage the tradeoff between protecting the database from running out of disk space and the stream failing because of log position loss.
Define a data retention policy for your database by running these Oracle Recovery Manager (RMAN) commands:
```
 TARGET 
  
 / 
 CONFIGURE 
  
 RETENTION 
  
 POLICY 
  
 TO 
  
 RECOVERY 
  
 WINDOW 
  
 OF 
  
 4 
  
 DAYS 
 ; 
```
You use the TARGET / command to start an RMAN client and connect to the source database. See Making Database Connections with RMAN .

We recommend that you retain backups and archive logs for a minimum of 4 days, and 7 days is recommended.

Running this command will restart your database instance so that the changes you made to the database can take effect.
Return to the SQL prompt of the database tool that you're using to configure the Oracle log file rotation policy. We recommend setting a maximum log file size of no more than 512MB.
Enable supplemental log data . To do so, first enable minimal database-level supplemental logging by running the following command:
```
 ALTER 
  
 DATABASE 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
 ; 
```
Next, choose whether to turn on logging for specific tables or the entire database.

To log changes only for specific tables, run the following command for each table that you want to replicate:
```
 ALTER 
  
 TABLE 
  
  SCHEMA 
 
 . 
  TABLE 
 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
  
 ( 
 ALL 
 ) 
  
 COLUMNS 
 ; 
```
Replace the following:
- SCHEMA : the name of the schema that contains the table.
- TABLE : the name of the table for which you want to log changes.
To replicate most or all tables in your database, consider turning logging on for the entire database. Run the following command to enable supplemental log data for the entire database:
```
 ALTER 
  
 DATABASE 
  
 ADD 
  
 SUPPLEMENTAL 
  
 LOG 
  
 DATA 
  
 ( 
 ALL 
 ) 
  
 COLUMNS 
 ; 
```
The supplemental logging mode must be set to ALL . You can't set this mode to PK_ONLY .

 GRANT 
  
 EXECUTE_CATALOG_ROLE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 CONNECT 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 CREATE 
  
 SESSION 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$DATABASE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
  
 -- for primary databases 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$STANDY_LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
  
 -- for standby databases 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$LOGFILE 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$ARCHIVED_LOG 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$LOGMNR_CONTENTS 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 SYS 
 . 
 V_$PARAMETER 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 EXECUTE 
  
 ON 
  
 DBMS_LOGMNR 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 EXECUTE 
  
 ON 
  
 DBMS_LOGMNR_D 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ANY 
  
 TRANSACTION 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ANY 
  
 TABLE 
  
 TO 
  
  USER_NAME 
 
 ;

If your database uses Transparent Data Encryption (TDE), grant the following permissions:

 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_TABLESPACES 
  
 TO 
  
  USER_NAME 
 
 ; 
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_ENCRYPTED_COLUMNS 
  
 TO 
  
  USER_NAME 
 
 ;

If your organization doesn't permit granting the GRANT SELECT ANY TABLE permission, use the solution described in the Oracle change data capture (CDC) section of the Datastream FAQ page.

If your source database is Oracle 12c or newer, then grant the following additional privilege:

 GRANT 
  
 LOGMINING 
  
 TO 
  
  USER_NAME 
 
 ;

For each command, replace

 USER_NAME

with the name of the user account. Also, running these commands will grant privileges to the user to read from V$DATABASE (which is required for validation), start the log miner, and grant privileges to select from V$LOGMNR_CONTENT .

Grant the user account SELECT access to the DBA_EXTENTS view in your database. This privilege lets you use the ROWID based backfill for your Oracle source:
```
 GRANT 
  
 SELECT 
  
 ON 
  
 DBA_EXTENTS 
  
 TO 
  
  USER_NAME 
 
 ; 
```

What's next

Learn more about how Datastream works with Oracle sources .